High Enantioselectivity Is Induced by a Single Monodentate Phosphoramidite Ligand in Iridium-Catalyzed Asymmetric Hydrogenation

摘要

Bidentate chiral ligands were the rule in metal-catalyzed asymmetric hydrogenation for more than 30 years[1] as chelation was believed to be necessary to impart the necessary rigidity to the metal complex for an efficient transfer of chirality. Recently, however, a few groups have demonstrated that monodentate ligands can also induce high enantioselectivity[2] as long as two of these ligands are present in the active species. Herein, we describe the first example of a highly asymmetric hydrogenation that is induced by a metal catalyst containing only one monodentate ligand.